This update is designed to reduce rankings for low-quality sites—sites which are low-value add for users, copy content from other websites or sites that are just not very useful. At the same time, it will provide better rankings for high-quality sites—sites with original content and information such as research, in-depth reports, thoughtful analysis and so on.

Few days back Google had released a Chrome Extension for allowing the users to block the unwanted sites in the Google's search results. You can freely download it from Chrome Web Store.

If you block any website using the Extension the website details will be sent to Google for doing more analysis about those blocked sites for tuning the algorithm further.

Google has said that the details collected from this site blocking extension is NOT used in this new algorithm change. But this algorithmic change addresses 84% of the Most-blocked sites of this Chrome Extension. So, this new algorithmic change will improve the search Quality of Google further.